The invention resides in an interface structure of a first—a tool or tool holder supporting—assembly and a second—a machining element supporting—assembly wherein the first assembly has a cavity with an at least a truncated cone- or cylinder-shaped section and a support surface or contact area which is effective in axial direction and wherein the second assembly is provided with a trunnion which has a cone- or truncated cone-shaped or cylindrical section for abutment on the cone- or truncated cone-shaped or cylindrical section of the first assembly and at least one in axial direction effective contact area or support surface for contacting the support surface or contact area of the first assembly.
Such an interface structure is known from DE 10 2010 026 129 B4. In the cavity of the first assembly, an annular shift lever element is arranged so as to be longitudinally movable or pivotable. The shift lever element has at least an engagement element for connection to the second assembly. The second assembly has at least one engagement element which, by a pivot movement of the second assembly, can be moved into engagement with the engagement element of the shift lever element. The size of an interface area with such a shift lever element is highly suited for relatively large interface area. However, with further miniaturizing of the interface area, the rigidity of the shift lever element decreases rapidly.
It is the object of the present invention to provide for a tool assembly interface structure between a first assembly and a second assembly which—in spite of a small interface area—ensures with each tool change simple handling with a high repetition accuracy concerning the position of the second assembly with regard to the first assembly.
The object is solved with the features of claim 1. Between the cavity and the trunnion-like projection there is a bayonet-like lock with at least one web provided on the trunnion-like projection. In the first assembly, a clamping element is arranged whose front end engages during clamping one of the webs.